Rapid curing and low-pressure phenol-formaldehyde resins



Patented June 10, 1952 UNITED STATES PATENT RAPIUCURING AND LOW=PBESSUR L EQEM EWPE EE1$ Amie; Anton. Johannes Sigtermans, The Hague, Netherland Wigner to Nederlandse Organiggtje. wool {Ioege1 s1:-Natuurwe1:enschappelijkv Qede mkt hehqe van Niive he i; fieedek en e ke r. The Hag Nethesleqda Ho; mowing. Applieatlon June -15,- QQQQ, 891%! N9- 2am mN er m e l a6; 4848- .1 le w mwxexee xe ereeeelie m he sew ll low-sprgss tin in laws 9? e a as between i b "as: s h fesl fire nge ammasme (21w Y Y 1942;-

Tlee- 9! menses? whiea m bevementii m a? the I BSQ H iQn $95 semexee pu ds xesmio l he e a cinolalseeem when 2.: nsive- For fifim le. xesine Mena e-dime a he e of Q; Phen ha s s t i e e aid a ma at a ebexm B e PIE?! seem r a at Q m: L: 5.219% o 2 1 1 be. amen ble Y5 ei moi-fi ms mat xielsh acids.

t m possible benene efio 'ig d lam -messes? tea -111$ about ms at sesemilqlfand am 1 aid 01 b a; 1421;? ea: xesommlend d exiqe a .agllg d. ix;

me one we? )1 an neries l ma l? E9941 emlte may be 9brginel e d-Selenium lone leagues; quantities Qieeizel sfi mix mayvary'somewhat acoording'to the nature of the phenol min used fi-t'axtme .m the mal phenol-formaldehyde condensate a very good wwgaressme resin'wasobtamed with-15% 'b: a catalyst mixture, consisting of z parts bywei'ght o1 seleniggg dioxide ggnog? weight of resorcinol use said resin had a. gigging time of 1 0 at mg C., and showed at essures g; 1, to 5 a ha deh ns' catelwm consis n very gg /cxnfi-a' good; adhesion fabgig, ager,

wood or the like.

od r sume; however; wereenso obtained with 107 of selenium dioxidg 10% of resoggino}, 5 of s niwa a 1%9! re;

sQril1Q%-' with lower e -mamas a; mixtu e the cu in fiim 190 usually the amount of baggie lowe than "19% and sm? h s-ed antes-ins.

1:12 is absolutel e-mix x'esq-rcinal, and a di Q d si th amen 0i. thene i dim .3 mateee mne si -net nefiemfihex e action on addition to the same resins, nd-gored fore do not show raniduggsing and/or good dssi n- Q f' szqeree'alsq p esm ess m a some? acid esters, variousfillers, pigments, etc. may-be added. The use 91; nlastiisers, however, is not neqeeee ryf mmi . new lie 9? e 479;. W1 59 i e wex mix z se a-as th 9. P. s e e to 59 HT? 9?? a 1 a d 1!?Q1ii12 the do an one; the he eweweeum to 50" C. and the water was separated by centrifugation, to produce a resin still containing 8 to 10% by weight of water. Theyield amounted to about-4.2 kg., or 3.8 kg. of water-free resin.

Thereupon so much denaturated 96% ethanol was added that a 50% resin solution was obtained, i. e. about 3.4 kg.

To this solution a mixture of 380 g. selenium V dioxide and a quantity of technical resorcinol varying from 190 to 380 g. was added.-

Example II I A so-called utility-fabric, having 17 warp threads per cm. and 13% woof threads per cm., and having a weight of 64. g. per m was impregnated with the solution, prepared according to Example I, which solution contained 10% of resorcinol and 10% of selenium dioxide based on the weight of the resin in the solution. After drying 60 to 80 g. of resin were found to have beenabsorbed per m? of fabric. If impregnation was carried out with a more dilute resin solution, less resin was absorbed.

Thereupon the treated fabric was cured at a temperature of 100 C. and a pressure of kg./cm. for min. The material thus acquired excellent mechanical properties. So the bending strength was 1030 kg./c'm. and the resistance to shock 110 kg./cm. measured with Schopper Dynstat 116.

I Example III 3 kg. of phenol and 3 kg. of a 33% formaldehyde solution are mixed and heated to 50 C. While stirring, whereupon 0.3 l. of ammonia solution is added and heating is continued while stirring. .As soon as the condensation reaction starts, the heating is interrupted and if necessary the reaction speed is reduced by cooling. After the first violent development of heat havingceased, heating is resumed till about 50 min. after the beginning of the condensation.

' Thereupon the reaction mixture is cooled down to about 50 C. and the water is removed either .by 'centrifugation or by vacuum distillation at low temperature (max. 50 C.). From the resulthaving aweight of .788 g. per m is impregnated. The impreg'natedpaper thereby takes up a quantity of resin. of 700 to 800g. per m. The paper is dried, either in theatmo-sphere or by a heated aircurrent of 40 C., whereafter it may be pressed into layers (e. g. 10 to 20 layers) under'a pressure or 2 /2 to 3 kg./cm. at a temperature of 100 C.

for 10min. In this way plates are formed having excellent mechanical properties and water- .resistance, which for .example may be used. for

making panels or for other building purposes.

I Example IV With the solutions, as described in Examples I and III, also mats may be impregnated, composed of cotton waste, artificial silk waste, wool waste,

straw fibres and "other fibrous materials. After drying in an air currentof about 40 C. such mats maybe pressed, either in one or in several layers, at pressures which may vary widely from ,2 /2 kg./cm. upwards. j The pressing temperature is 100 C., the pressing time 12 to 15 min. The pressing may be accomplished between flat plates, but also between dies imparting a certain shape to thematerial. In the latter way articles, may be'molded which are more or less hollow and thin-walled, e. g. trunks, boxes, hat boxes, spherical objects and the like. The nature of the materialafter curing at C. dependson the quantity of absorbed resin (which may be adjusted by variation of the solution) and on the pressure applied. Thus flexible, somewhat porous to harder non-porous sheeted materials are obtained.

I claim:

1. Process of producing a rapid curing, low pressure phenol-formaldehyde resin which comprises reacting phenol and formaldehyde in stoichiometric proportions to form the phenol formaldehyde resin and water, removing the water from said resin, dissolving said resin in a volatile organic solvent, and adding to said resin solution about 15-25% by weight of the resin of a hardening agent consisting essentially of about 2-1 parts by weight of resorcinol and about 1-2 parts by weight of selenium dioxide.

2. Process of producing a rapid curing, low .pressure phenol-formaldehyde resin which comprises adding at least about 10% by weight of the resin of a hardening agent consisting essentially of about 2-1 par-ts by weight of resorcinol and about 1-2 parts by Weight of selenium dioxide to the preformed phenol-formaldehyde resin, and recovering a rapid curing phenol-formaldehyde resin.

3. Process of producing a rapid curing, low pressure phenol-formaldehyde resin which comprises reacting phenol and formaldehyde in stoichiometric proportions to form the phenol-- formaldehyde resin, and adding to said resin about 15-25% by weight of said resin of a hardening'agent consisting essentially of about 21 parts by weight of resorcinol and about 1-2 parts by weight of selenium dioxide.

4.. Process of producing a rapid curing, low pressure phenol-formaldehyde resin which comprises reacting phenol and formaldehyde in stoichiometric proportions to form the phenolformaldehyde resin, and adding to said resin about 20% by weight of said resin of a hardening agent consisting essentially of resorcinol and selenium dioxide in equal amounts.

5. A laminated material of excellent mechanical properties, impregnated with a rapid curing, low pressure phenol-formaldehyde resin containing a hardening agent consisting essentially of about 10% resorcinol and about 10% selenium dioxide by weight of the resin, each of said layers being impregnated prior to assemblythereof.

6. Shaped articles of excellent mechanical properties comprising a fibrous material impregnated with a rapid curing, low pressure phenolformaldehyde resin containing about 15-25% by weight of the resin of a hardening agent consisting essentially of about 2-1 parts by weight of resorcinol and about 1-2 parts by weight of selenium dioxide.

ARIE ANTON J OHANNES SIGTERNIANS.

REFERENCES oirsn The following references'are of record in the file of this patent:

UNITED STATES PATENTS I Date 

3. PROCESS OF PRODUCING A RAPID CURING, LOW PRESSURE PHENOL-FORMALDEHYDE RESIN WHICH COMPRISES REACTING PHENOL AND FORMALDEHYDE IN STOICHIOMETRIC PROPORTIONS TO FORM THE PHENOLFORMALDEHYDE RESIN, AND ADDING TO SAID RESIN ABOUT 15-25% BY WEIGHT OF SAID RESIN OF A HARDENING AGENT CONSISTING ESSENTIALLY OF ABOUT 2-1 PARTS BY WEIGHT OF RESORCINOL AND ABOUT 1-2 PARTS BY WEIGHT OF SELENIUM DIOXIDE. 